Three‐Component Reaction for Construction of Spiro[indoline‐3,7′‐thiazolo[3,2‐a]pyridines] and Spiro[benzo[4,5]thiazolo[3,2‐a]pyridine‐3,3′‐indolines]

The three‐component reaction of thiazole (benzothiazole), dialkyl but‐2‐ynedioate, and isatinylidene malononitriles in toluene at 110–120°C in a sealed tube afforded a mixture of cis/trans‐isomers of functionalized diastereoisomeric spiro[indoline‐3,7′‐thiazolo[3,2‐a]pyridines] and spiro[benzo[4,5]thiazolo[3,2‐a]pyridine‐3,3′‐indolines] in good yields. Both cis‐isomers and trans‐isomers were successfully separated out and fully characterized with spectroscopy and single crystal determination. Under similar conditions, the three‐component reaction containing 2‐(1,3‐dioxo‐1H‐inden‐2(3H)‐ylidene)malononitrile resulted in spiro[indene‐2,7′‐thiazolo[3,2‐a]pyridine] derivatives.     

Multicomponent Efficient Synthesis of New [1,2,4]Triazolo[3,4]thiadiazines

A series of novel triazolo thiadiazines were synthesized by a simple, highly efficient, one‐pot pseudo four component approach involving the condensation of 4‐amino‐5‐hydrazinyl‐4H‐1,2,4‐triazole‐3‐thiol ( 1 ), aromatic aldehydes ( 2 ), and various phenacyl bromides ( 3 ) with good yields. The structures of compounds were confirmed by analytical and spectral (IR, ¹H NMR, ¹³C NMR) data.     

One‐Pot Three‐Component Synthesis of 6H‐chromeno[4,3‐b] or Cyclopenta[b]furo[3,2‐f]quinoline Derivatives

Two series of furo[3,2‐f ]quinoline‐2‐carboxylate were obtained via a three‐component reaction of aldehydes, 5‐aminobenzofuran‐2‐carboxylate, and 4‐hydroxy‐2H‐chromen‐2‐one or cyclopentane‐1,3‐dione in DMF under catalyst‐free condition in high yields. This one‐pot three‐component reaction provided an efficient method for the synthesis of fused polycyclic heterocycles for bioactive screening.     

Spiro[pyrido[3,2,1‐ij]pyrimido[4,5‐b]quinoline‐7,5′‐pyrrolo[2,3‐d]pyrimidines] and Spiro[pyrimido[4,5‐b]quinoline‐5,1′‐pyrrolo[3,2,1‐ij]quinolines] Derived from 5,6‐Dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione

Reaction of 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione ( 1 ) with two equivalents of some 6‐aminouracils (or 6‐amino‐2‐thiouracil) generates spirocyclic tetrahydrobenzo[if]quinolizines ( 7 ). The one‐pot, three‐component reaction of amido ketone ( 1 ) with 6‐aminouracil (or 6‐amino‐2‐thiouracil) and a cyclic six‐membered 1,3‐diketone produces spirocyclic tetrahydropyrrolo[3,2,1‐ij]quinolinones ( 15 ).     

Synthesis and Cytotoxic Activity of Some Novel Dihyrobenzo[h]pyrano[3,2‐c]chromene Derivatives

Three‐component reaction of 4‐hydroxy‐2H‐benzo[h]chromen‐2‐one, aromatic aldehydes, and malononitrile in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) in ethanol at room temperature affords good yields of novel dihyrobenzo[h]pyrano[3,2‐c]chromene derivatives. The synthesized compounds examined by MTT assays for cytotoxic activity in two human cancer cell lines (MOLT‐4, HL‐60). Most of the evaluated compounds showed low inhibitory activity against tumor cell line at micromolar concentrations.     

Convenient Synthesis of Spiro[benzo[d]pyrrolo[2,1‐b]thiazole‐3,2′‐indenes] Derivatives via Three‐Component Reaction

The three‐component reaction of N‐phenacylbenzothiazolium bromides, aromatic aldehydes and indane‐1,3‐dione in ethanol at room temperature in the presence of triethylamine as base afforded functionalized spiro[benzo[d]pyrrolo[2,1‐b]thiazole‐3,2′‐indenes] in good yields and with high diastereoselectivity. The ¹H NMR data and single crystal structure clearly indicated that the obtained spiro compounds predominately have one diastereoisomer.     

The synthesis of [1]benzothieno[2,3-c]quinolines, [1]benzothieno[2,3-c][1,2,4]triazolo[4,3-a]quinoline,and [1]benzothieno[2,3-c]tetrazolo[1,5-a]quinoline

Photocyclization of 3-chloro-N-phenylbenzo[b]thiophene-2-carboxamide 10 afforded [1]benzothieno[2,3-c]-quinolin-6(5H)-one 11 which was chlorinated to 6-chloro[1]benzothieno[2,3-c]quinoline 12 followed by dechlorination to give [1]benzothieno[2,3-c]quinoline 5 . A series of 6-substituted alkoxy and thioalkoxy[1]benzothieno[2,3-c]quinoline derivatives were prepared along with the N-methyl quaternary salt 13 of 5 . 6-Chloro[1]-benzothieno[2,3-c]quinoline 12 was converted into 6-hydrazino[1]benzothieno[2,3-c]quinoline 23 which upon treatment with formic acid yielded [1]benzothieno[2,3-c][1,2,4]triazolo[4,3-a]quinoline 6 . Treatment of 23 with nitrous acid resulted in [1]benzothieno[2,3-c]tetrazolo[1,5-a]quinoline 7 . Compounds 6 and 7 are novel heterocyclic ring systems.     

Regioselectively Synthesis of Thiazolo[4,5‐a]acridines and Oxazolo[5,4‐a]thiazolo[5,4‐j]acridines via Multicomponent Domino Reactions

A regioselective three‐component reaction of aromatic aldehydes, 2‐hydroxy‐1,4‐naphthoquinone and benzo[d]thiazol‐5‐amine in HOAc under microwave irradiation has been developed. A series of new thiazolo‐fused benzo[h]acridines were synthesized with high chemical yields in this one‐pot reaction. The resulting thiazolo‐fused acridines were employed to further react with aldehydes and ammonium acetate to give polycyclic‐fused oxazolo[5,4‐a]thiazolo[5,4‐j]acridines. The present synthesis shows several advantages, such as operational simplicity, fast reaction rates, which makes it a useful and attractive process of library generation for drug discovery.     

An Efficient Synthesis of Benzo[g]thiazolo[2,3‐b]quinazolin‐4‐ium and Benzo[g]benzo[4,5]thiazolo[2,3‐b]quinazolin‐14‐ium Hydroxides by a One‐pot,Three‐component Reaction under Green Conditions

A new series of benzo[g]thiazolo[2,3‐b]quinazolin‐4‐ium and benzo[g]benzo[4,5]thiazolo[2,3‐b]quinazolin‐14‐ium hydroxide derivatives have been synthesized by the one‐pot, three‐component reaction of aryl glyoxal monohydrates, 2‐hydroxy‐1,4‐naphthoquinone, and 2‐aminothiazole or 2‐aminobenzothiazole in the presence of triethylamine and p‐toluenesulfonic acid as organocatalysts in H₂O/acetone (2:1) at room temperature. This method offers mild reaction conditions, excellent yields, easy workup, and readily accessible starting materials and catalysts.     

The synthesis of benzo[b]phenanthro[d]thiophenes and anthra[b]benzo[d]thiophenes

The synthesis of benzo[b]phenanthro[2, 3-d]thiophene ( 5 ), benzo[b]phenanthro[4, 3-d]thiophene ( 6 ), benzo-[b]phenanthro[2, 1-d]thiophene ( 9 ), benzo[b]phenanthro[3, 2-d]thiophene ( 14a ), anthra[1, 2-b]benzo[d]thiophene ( 24 ), anthra[2, 3-b]benzo[d]thiophene ( 29 ) and anthra[2, 1-b]benzo[d]thiophene ( 30 ) is described as well as the preparation of 13-methylbenzo[b]phenanthro[3, 2-d]thiophene ( 14b ).     

New [g]-fused [1,2,4]triazolo[1,5-c]pyrimidines: Synthesis of pyrido[3,2-e] and [4,3-e][1,2,4]triazolo[1,5-c]pyrimidine,pyrimido[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine and [1,2,4]triazolo[1,5-c]pteridine derivatives

A number of 2-aryl-substituted pyrido[3,2-e] and [4,3-e][1,2,4]triazolo[1,5-c]pyrimidines and [1,2,4]triazolo[1,5-c]pteridines 11,12a,b,e , their corresponding 5-carbonyl derivatives 7,8a,b,e and some pyrimido[5,4-e][1,2,4]triazolo[1,5-c]pyrimidin-5-ones 7,8c,d have been synthesized, according to different pathways. The new tricyclic heterocycles were prepared with the aim of studying their possible benzodiazepine receptors affinity.     

New heterocyclic structures. [1,3]Thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d][1,3]thiazino[3,2-a]pyrimidine

Derivatives of two new molecular structures, namely, [1,3]thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d]-[1,3]thiazino[3,2-a]pyrimidine, were synthesized together with other heterocyclic compounds. Retrosynthetic analysis of their molecular skeletons suggested a simple way of obtaining 3,4-dihydro-7,8-diamino-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, which is a useful intermediate for their synthesis. This intermediate and the thiazole homologue were obtained directly by reaction of 5,6-diamino-2,3-dihydro-2-thioxo-4(lH)-pyrimidi-none with 1,3- or 1,2-dibromoalkane, respectively.     

A New Four‐Component Reaction for the Synthesis of Spiro[4H‐indeno[1,2‐b]pyridine‐4,3′‐[3H]indoles]

A new four‐component synthesis of spiro[4H‐indeno[1,2‐b]pyridine‐4,3′‐[3H]indoles] and spiro[acenaphthylene‐1(2H),4′‐[4H‐indeno[1,2‐b]pyridines] by the reaction of indane‐1,3‐dione, 1,3‐dicarbonyl compounds, isatins (=1H‐indole‐2,3‐diones) or acenaphthylene‐1,2‐dione, and AcONH₄ in refluxing toluene in the presence of a catalytic amount of pyridine is reported.     

Synthesis of New Chromeno[4,3‐b]pyrazolo[4,3‐e]pyridines Derivatives with Antimicrobial Evaluation

A series of 2‐oxo‐2,5‐dihydro‐1H‐chromeno[4,3‐b]pyridine derivatives were obtained by using a one‐pot three component reaction of 2,2‐disubstituted chroman‐4‐one with aromatic aldehydes and 2‐cyanoacetamide in the presence of sodium hydroxide under solvent‐free conditions. Heating chromenopyridine derivatives with phosphoryl chloride gave the corresponding chloro derivatives. The reaction of the chloro derivatives with hydrazine hydrate afforded dihydrochromeno[4,3‐b]pyrazolo[4,3‐e]pyridines derivatives. Condensation of the dimethyl derivative compound with the aromatic aldehydes gave 8‐Arylideneamino‐6,6‐dimethyl‐10H‐chromeno[4,3‐b]pyrazolo[4,3‐e]pyridine.     

Synthesis of anthra[b]thiophenes and benzo[b]naphtho[d]thiophenes

All isomers of the parent anthra[b]thiophenes and benzo[b]naphtho[d]thiophenes, namely anthra[2,3-b]thio-phene, anthra[2,1-b]thiophene, anthra[1,2-b]thiophene, benzo[b]naphtho[2,3-d]thiophene, benzo[b]naphtho[2,1-d]thiophene and benzo[b]naphtho[1,2-d]thiophene were synthesized using a new procedure.     

A Diastereoselective Synthesis of Functionalized Tetrahydroindeno[2′,1′,3,4]pyrido[2,1‐a]isoquinolines

An effective route to alkyl 9a‐(2,3‐dihydro‐1,3‐dioxo‐1H‐inden‐2‐yl)‐9a,14,14a,14b‐tetrahydro‐14‐oxoindeno[2′,1′:3,4]pyrido[2,1‐a]isoquinoline‐9‐carboxylates via a diastereoselective one‐pot four‐component reaction of isoquinoline and alkyl prop‐2‐ynoates with two equivalents of indane‐1,3‐dione, in aqueous MeOH at room temperature, is described.     

An Efficient Method for the Synthesis of Naphtho[2,3‐f]pyrano[3,4‐c]quinoline Derivatives Catalyzed by Iodine

A mild and efficient method for the synthesis of naphtho[2,3‐f]pyrano[3,4‐c]quinoline derivatives via three‐component reaction of aromatic aldehyde, anthracen‐2‐amine, and tetrahydropyran‐4‐one is described using iodine as catalyst. The features of this procedure are mild reaction conditions, good to high yields, and operational simplicity.     

An Efficient Synthesis and Fluorescent Properties of Pyrazole[3,4‐b]thieno[2,3‐e]pyridine Derivatives

A simple and efficient method for the synthesis of pyrazole[3,4‐b]thieno[2,3‐e]pyridine derivatives via the sequence of three‐component, catalyst‐free, and solvent‐free condensation and oxidation was described. The products feature a donor‐π‐conjugated acceptor fluorescent activity system, and the fluorescence emission wavelength was measured in methanol. Some products were fluorescent in solution emitting at blue light (λ_em = 430–505 nm).     

Calculation of 1H chemical shifts of [n]annuleno[m]annulenes and [n]annulenyl[m]annulenes

The ring current and local anisotropic contributions to the ¹H chemical shifts of [n]annuleno[m]annulenes and [n]annulenyl[m]annulenes with n, m = 12, 14, 18 and n, m = 13, 15 are calculated. The agreement between experimental and calculated shifts for the few known compounds is very good so that the predictions for the as yet unknown compounds are reliable. The effect of an annulene ring on the shifts of the protons at the other ring in these bicyclic compounds is discussed for several types of fusion of the two constituent annulenes.     

Synthesis of a Novel Heterocyclic System, [1,2,4] Triazino[1,2-a]Pyrimido [4,5-e] [1,3,4] Thiadiazines

Substituted 6-chloro-pyrimido[4,5-e][1,3,4] thiadiazine was converted to the corresponding 6-hydrazino derivative by treatment with hydrazine hydrate in DMF/Et ₃ N. The latter was converted to various substituted [1,2,4]triazino[1,2-a] pyrimido[4,5-e][1,3,4]thiadiazines.